FIG. 2.

Phylogenetic tree generated by the neighbor-joining method for the combined data for the purN, thrB, trpB, and mdh-argR regions sequenced to give a total of 3,390 bp. Strain names prefixed with M are EIEC and are followed by serotype and biochemical properties for mucate and acetate if negative as M- and A-respectively; for Shigella strains, F denotes S. flexneri, D denotes S. dysenteriae; B denotes S. boydii, and SS denotes S. sonnei, followed by the serotype number. Bootstrap values are percentages of 1,000 replications and, if 50% or greater, are indicated at the nodes. LT2 is used as the outgroup.